pin down specific ansible version to be used with our playbook

requirements.txt

@@ -0,0 +1,18 @@
+ansible==2.2.1.0
+appdirs==1.4.3
+asn1crypto==0.22.0
+cffi==1.10.0
+cryptography==1.8.1
+enum34==1.1.6
+idna==2.5
+ipaddress==1.0.18
+Jinja2==2.8.1
+MarkupSafe==1.0
+packaging==16.8
+paramiko==2.1.2
+pkg-resources==0.0.0
+pyasn1==0.2.3
+pycparser==2.17
+pycrypto==2.6.1
+PyYAML==3.12
+six==1.10.0